Container closure



July 27, 1965 w. T. SAUNDERS CONTAINER CLOSURE 2 Sheets-Sheet 1 Filed Nov. 21, 1963 INVENTOR. w/zz/A/w I 540N176 A 5 July 27, 1965 w. T. SAUNDERS CONTAINER CLOSURE 2 Sheets-Sheet 2 Filed Nov. 21, 1963 INVENTOR. W/ZZ/AM I S/il/lVDf/RS' BY p 4770 9/Vfy United States Patent 3,197,167 CONTAINER CLGSURE William T. Saunders, Weirton, W. Va, assignor to American an Company, New York, N.Y., a corporation of New .lersey Filed Nov. 21, 1963, Ser. No. 325,359 6 Claims. (Cl. 229-55) The present invention relates to double seams for joining metal ends to fibre bodies, and has particular reference to such a seam which is highly resistant to forces, both internal and external, which operate to separate the end from the body.

Because of recent technological developments, the use of composite containers having fibre bodies and metal cnd closures has substantailly increased. Such containers are suitable for use in holding liquid products such as motor oil which are quite heavy and which thus subject the container to substantial pressures during normal, as well as abnormal handling of the filled container.

Frequently, filled containers are dropped with such severity, even during normal handling, that the internal pressures which are exerted by the product against the bottom container end tends to force the end axially of the body in such manner that the body flange pulls out of the end seam, with the result that the container becomes a leaker.

In addition, when a number of filled cans are closely packed within a shipping case and shipped through normal channels of transportation, certain of the juxtaposed cans have a tendency to override the adjacent cans, because of the vibrations encountered during such shipping, in such manner that the end seam of one can repeatedly hits against the body of an adjacent can longitudinally inwar ly of its end seam, thus exertin an inward pressure against the body which tends to cause the adlacent portion of the flange of the body to pull out of the end seam to thereby cause leakage through the end seam.

The present invention is designed to overcome these problems by providing a composite can double seam of special configuration which exerts greater holding power on the fibrous body than do the heretofore used composite can double seams.

This result is attained by providing a construction which incorporates what is herein designated as a pinch pocket effect wherein the reversely bent fibre body is gripped more tightly at its base, i.e. adjacent its line of fold-than at its extremity, the gripping action being effected to a great extent by the raw, terminal edge of the metal end which bites into the body flange. As a result of this construction, there is obtained a considerably increased resistance to movement of the body flange in the seam, since such movement necessarily entails the pull ing of a thicker, less compressed flange portion through an area of constriction and against the bite of the edge of the end, and thus requires substantial further compression of the fibre material of the flange in order to pull the flange from the pinch pocket.

The pinch pocket is obtained by shaping the outer wall of the metal end portion which is incorporated in the double seam in such manner that it slopes in a direction which is substantially the reverse of that of the conventionally used double scam. in other words, this wall, instead of extending vertically or being angled inwardly from the top of the double seams towards the body, as in conventional seams, is flared outwardly away from the body so that the bottom portion of the end seam is substantially wider than the top portion, thus providing the extra space necessary to produce the pinch pocket when the terminal edge portion of the metal end is bent upwardly and outwardly towards the flared end Wall to clamp the body flange between it and this flared wall. Thus, there is obtained a true double seam wherein substantially all of the fibre within the seam is compressed to some extent, but wherein a localized additional compression is exerted by the terminal end portion of the metal end to provide increased resistance to relative movement between the body and end flanges.

L1 addition to this pinch pocket structure, the metal end portion of the double seam is provided with a structure which provides a continuing spring action or cushioning effect which absorbs a substantial portion of the forces which are exerted against the bottom end of the container by its contents When the filled container is dropped or otherwise subjected to strong impact forces. As a result of this absorption of the kinetic energy of the contents upon impact, the tendency of the end seam to rupture is further reduced.

An object of the invention therefore is the provision of a double seam for a composite can which is highly resistant to leakage when subjected to external or internal pressures.

Another object of the invention is to provide such a seam which is highly resistant to blow-oil, i.e. internal pressures exerted against the end which tend to blow-off or separate the end from the can.

A further object of the invention is the provision of an end seam which is resistant to flange pull-out when the body is deformed inwardly by impact.

A further object of the invention is the provision of a composite double seam wherein the configuration of the seam is such as to provide a flexing action which absorbs some of the irnpact energy when the container is dropped or otherwise subjected to shock.

Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description, which, taken in connection with the accompanying drawings, discloses a preferred embodiment thereof.

Referring to the drawings:

FIGURE 1 is a perspective view of a sealed composite can formed with double seams made according to the principles of the instant invention;

FlG. 2 is a greatly enlarged section taken substantially along the line 2-2 in FIG. 1; and

FIGS. 3 and 4 are views corresponding to FIG. 2 but showing how the seam is flexed when the filled container is subjected to shock impact, to thereby absorb some of the impact energy.

As a preferred and exemplary embodiment of the instant invention, PEG. 1 illustrates a sealed can ill which comprises a fibrous body 12 having its opposite ends closed by means of metal end closure members 14 which are secured to the body in double seams 16 which embody the principles of the instant invention.

The body 12 may be of any suitable type, but as illustrated in the draw ngs is or" the spirally wound type and comprises first and second body plies lit, 29, formed of a stron web material such as kraft paper and having their helical edges abutted together, an external label ply 22, and an inner liner ply 24. The helical edges of the plies 2-2, 24 may be overlapped in the usual manner (not shown). All of the mutually engaging surfaces of the plies 18, 2h, 22 and 24 are secured together by suitable adhesives.

The metal end members 14 are preferably substantially identical in construction and are formed of flexible thin sheet metal such as light gauge tin plate or aluminum alloy. Each end member 14 is formed with a depressed imperforate panel 2% which merges into an upstanding annular countersink wall 23 which is inset into and frictionally engages within a peripheral end portion Ell of the body 12, this wall 28 being upwardly and outwardly inclined to some degree so that the seaming chuck which is disposed inwardly of it during the seaming operation may be readily withdrawn at the completion thereof. In the seam construction illustrated in FIG. 2, the wall 28 is inclined about 4 from the vertical.

The marginal end portion of the body 12 is formed into a flange 32 which is reversely bent outwardly and downwardly around a line of fold indicated by the dot and dash line F in FIG. 2.

At the top of the countersink wall 23, the end member 14 is bent sharply outwardly along a sharp annular inner radius or corner 36 and extends horizontally outwardly in a flat annular end Wall 38 of substantial width, and is then reversely bent outwardly and downwardly around a relatively sharp annular outer radius or corner 39 to form an inclined annular outer wall 49 which at its bottom end is bent inwardly and upwardly around the body flange 32 in a hook 42 having a raw edge 44 which is indented into the body flange 32'adjacent the base thereof. The outer wall 40 is preferably inclined about 9 from the vertical, its direction of inclination being opposite to that of the countersink wall 28.

As seen in FIG. 2, all portions of the fibre body 12 which are included within the end seam 16 are compressed to some extent in order to form a tight, solid structure. Thus, the portion 30 is compressed between the countersink wall 23 and the hook 42; the body portion on both sides of the line of fold F is compressed between the countersink wall 28, the flat annular end wall 38, and the flared outer wall 49; and the flange 32 is compressed between the hook 42 and the outer wall 43.

While all of these fibre body portions within the end seam 16 are compressed to some extent, they are not overcompressed to the extent that their fibrous structures are so thinned that there is danger of their being cut through. This limited compression is made possible by the substantial width of the flat annular end wall 38 which accommodates the body in the area of the line of fold F, and the outward and downward inclination of the outer wall 40 of the metal end member 14 which provides sufficient width in the area of the hook 42 to prevent over-compression of the body flange 32 and body wall portion 30.

By virtue of this construction, it will be seen that the hook 42 and the lower portion of the outer wall 46 define what may be termed a pinch pocket; indicated generally by the letter P, since in eflfect the flange 32 is pinched off from the balance of the body by the indenting of the raw edge 44 of the end hook 42 into the flange 32 to form an annulararea of constriction which is centered generally along the plane indicated by the dot and dash line C in FIG. 2.

As a result of this pinching eflect, the resistance of the seam to forces which tend to pull the body flange 32 from the pocket P is substantially increased, since, in order to pull the flange 32 from the pinch pocket P it is necessary that the thicker, less-compressed flange portion in the pocket P be pulled through the area of constriction.

In addition to the increased resistance to flange pullout provided by the pinch pocket P, the resistance of the seam to impact forces is also enhanced by a flexing or hinging action which is provided by the angular relationship of the walls 28, 38 and 40 and by the fact that they are joined in relatively sharp radii or corners 36, 39 which provide definite flex or bend lines when the end closure 26 is subjected to internal pressures, as will hereinafter be explained.

When the contents C of the container are comparatively heavy, as when they comprise a liquid such as motor oil, and the container is dropped, the inertia of the contents C exerts a strong pressure upon the bottom end of the container at the moment of impact. This impact force tends to push the end longitudinally of the body, and thus to pull the body flange 32 out of the pocket P.

In the instant seam, however, much of the force of impact is absorbed by a flexing of the closure 14 around the radii 36, 39 with the result that less of the impact force is available to pull the flange out of the pinch pocket P than would otherwise be the case.

As seen in FIG. 3, at the moment of impact the weight of the liquid forces the end member 14 axially relative to the body 12 so that a portion of the force thus exerted against the end member is absorbed by the end seam by virtue of a flexing of the end wall 38 around the outer radius 39, this flexing thus resulting in an increase in the obtuseness of the angle between the end wall 38 and the outer wall 48 and the creation of a gap 46 between the end of the body 12 and the end wall 38. This flexing provides a spring action or cushioning elfect which has the result of absorbing some of the kinetic energy of the liquid in the dropped 'container and thus reducing the tendency of the body flange to pull out of the pinch pocket P.

It should be stated at this point that the flexing actions of the seam, as illustrated in FIGS. 3 and 4, are normally undergone only by the seam at the bottom end of the container when the container is dropped, and that the seam at the upper end of the dropped container will normally not be subjected to suilicient pressures at the moment of impact to cause it to flex in the illustrated manner. However, for purposes of clarity of illustration, e.g.in order to make it easier to compare the flexed seam with the normal seam of FIG. 2, the seam of FIGS. 3 and 4, while actually being the bottom seam of the container, has been shown in upright position. In addition, the contents C of the container have been omitted from FIGS. 3 and 4.

If the impact is severe enough to result in continued endwise movement of he end member 14, it produces an outward bulging of the depressed panel 26 which results in a reduction of its diameter and consequently in a pulling away of the base portion of the countersink wall 28 from the body wall portion 39. This in turn rocks the end of the countersink wall 23 adjacent the corner 36 outwardly, and has the effect of pushing the end wall 38 outwardly, thereby effecting a hinging action in the outer wall 4t and hook 42 which has the eflfect of causing the wall 4% to move from its initially inclined position toward a straight position where it is substantially parallel to the body wall 12 (as seen in full lines in FIG. 4), in which position there is still little or no tendency of the flange 32 to pull out of the pocket P. The rocking of the wall 40 and hook 42 may continue until these parts, and the flange portion enclosed within the pocket P, actually assume an inclination which is in the opposite direction to their original inclination without having the flange pull out of the pinch pocket P, since in this oppositely inclined position the relative positions of the flange 32 and the outer Wall 40 and hook 42 closely approach the positions which these parts occupy in a conventional double seam.

Thereafter, continued bulging of the end panel 26 and a continued reduction in its diameter results in a flexing of the countersink wall 28 around the inner radius 35, thus causing the various portions of the end to assume the contour shown in dot and dash lines in FIG. 4, and increasing the angle between the countersink wall 28 and the end wall 38. During this flexing action, the wall 40 remains substantially stationary in its inwardly inclined position (which is shown in dot and dash lines in FIG. 4) since its resistance to further rocking is greater than the force required to flex the radius 35 to produce a more obtuse angle between the countersink wall 28 and the end Wall 38. There may also be some additional flexing of the corner 39 during this flexing of the radius 36, but this is comparatively slight.

As a result of these combined flexing and rocking movements of the end seam, together with the increased resistance to body flange pull-out which is provided by the pinch pocket P, the seam of the instant invention is markedly superior to conventional seams in resisting pressures which tend to open up the seam and thereby eiiect leakage of the container contents C.

It will of course be realized that the shock absorptive capabilities of the seam are not limitless and that if the impact is unusually severe, the seam will rupture and leak. Nevertheless, the instant seam is a decided improvement over the heretofore conventional seam.

The following is an example of the various dimensions of a seam of the instant type which provides superior holding characteristics:

Thickness of end closure stock (aluminum alloy) =inch .0094 Thickness of body do .038 Vertical height of seam do .115 Thickness of seam do .085 Vertical inclination of outer wall 40 9 Thus, whereas when conventional seams are used, the end members normally blow-ofl? from the body when the interior of the body is subjected to pressures of about 20 pounds per square inch, when the seam of the instant invention is utilized, the blow-off pressure is increased to about 24 or 25 pounds per square inch.

In addition, whereas the body flange pulls out of the conventional seam when subjected to approximately 35 inch-pounds of pendulum impact in a standard pendulum impact test, an impact of 45 inch-pounds is required to elfect a pull out when the instant seam is utilized. (To run a pendulum impact test, a pendulum having secured to its bottom end a weight having a contour similar to the contour of the seam being tested is allowed to drop against the wall of the body of the container being tested, the point of impact of the seam-contoured portion of the Weight being disposed at a distance of above the bottom seam of such container and being efiected when the pendulum arm has been permitted to drop to a substantially vertical position.)

Such performance gains are correlated to the performances of the filled containers, and frequently are the difierence between container failure and success.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description and it will be apparent that various changes may be made in the form, construction, and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

I claim:

1. A composite container having a fibrous body secured to a metal closure in a double seam, said body extending reversely back on itself to form a flange and said closure being formed with a countersink wall which is set into said fibrous body radially inwardly of said body flange, said closure extending outwardly from said countersink wall over the end of said body in an annular end wall, then downwardly and outwardly in an inclined outer wall which is disposed outwardly of said body flange, and then upwardly in a closure hook which is disposed inwardly of said body flange, said body flange being compressed in a closed pinch pocket formed between said outer closure wall and said closure hook, the terminal edge portion of said closure hook being indented into said body flange to form an area of constriction spaced above the terminal edge of said body flange to increase the resistance of the seam to forces tending to pull said body flange out of said pinch pocket.

2. The container of claim 1 wherein said outer closure wall is inclined outwardly and downwardly at an angle of about 9 from the vertical.

3. The container of claim 1 wherein said end wall is flat and is disposed in obtusely angled relationship with said outer wall to provide a flexing action when the-metal closure is subjected to internal pressure to thereby reduce the possibility of movement of said outer wall outwardly from said body flange.

4. The container of claim 3 wherein said end wall and said outer wall are joined in a radius which is sufliciently sharp to provide a line of flexing.

5. The container of claim 4 wherein said end wall is disposed in obtusely angled relationship to saidcountersink wall to provide a flexing action which becomes effective subsequent to the first mentioned flexing action of claim 3;

6. The container of claim 5 wherein said end wall and said countersink wall are joined in a radius which is sufliciently sharp to provide a line of flexing.

References Cited by the Examiner UNITED STATES PATENTS 700,576 5/02 Thompson 220-67 2,196,206 4/ Foss 220-67 2,277,066 3/42 Bogner 220-67 2,346,165 4/44 Hothersall 220-67 2,346,619 4/ 44 Schrader 220-67 3,009,626 11/61 Johnson 229-51 3,072,517 1/ 63 Gaylord 2295.5 X

FRANKLIN T. GARRETT, Primary Examiner. GEORGE O. RALSTON, Examiner. 

1. A COMPOSITE CONTAINER HAVING A FIBROUS BODY SECURED TO A METAL CLOSURE IN AW DOUBLE SEAM, SAID BODY EXTENDING REVERSELY BACK ON ITSELF TO FORM A FLANGE AND SAID CLOSURE BEING FORMED WITH A COUNTERSINK WALL WHICH IS SET INTO SAID FIBROUS BODY RADIALLY INWARDLY OF SAID BODY FLANGE, SAID CLOSURE EXTENDING OUTWARDLY FROM SAID COUNTERSINK WALL OVER THE END OF SAID BODY IN AN ANNULAR END WALL, THEN DOWNWARDLY AND OUTWARDLY IN AN INCLINED OUTER WALL WHICH IS DISPOSED OUTWARDLY OF SAID BODY FLANGE, AND THEN UPWARDLY IN A CLOSURE HOOK WHICH IS DISPOSED INWARDLY OF AID BODY FLANGE, SAID BODY FLANGE BEING COMPRESSED IN A CLOSED PINCH POCKET FORMED BETWEEN SAID OUTER CLOSURE WALL AND SAID CLOSURE HOOK, THE TERMINAL EDGE PORTION OF SAID CLOSURE HOOK BEING INDENTED INTO SAID BODY FLANGE TO FORM AN AREA OF CONSTRICTION SPACED ABOVE THE TERMINAL EDGE OF SAID BODY FLANGE TO INCREASE THE RESISTANCE OF THE SEAM TO FORCES TENDING TO PULL SAID BODY FLANGE OUT OF SAID PINCH POCKET. 